Improve date picker

[Varamil]

Describe the problem to be solved

For the date picker:

It would be nice to have these improvements:

• Display week number, this numbering is commonly used, and this improvement would avoid to look for another calendar for correspondance.
• Automatically close the picker when a date or Today is selected. Currently you need to clic elsewhere, but if it is not in the same widget the picker stay open. And in all cases, as we can select only one date a time (not a start/end for a period) I don't see why we would like to keep the popup open.

Describe the solution you would like

Week number
Add a column on the left or on the right (not clickable, only display)

Automatic close
Simply, when we click on a date or Today shortcut, when the cell value has been updated, close to popup